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platform_build_soong
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Propagate PGO instr. flags to dependencies of a static lib 

Bug: http://b/119560349
Bug: http://b/168925229

To build with PGO instrumentation, the link step also needs
-fprofile-generate flag.  Omitting this will result in a linker error.
This surfaces if module A depends on module B but PGO is used only for
module B.

Previous uses of PGO were avoiding or working around the issue but to
accommadate recent changes, this CL propagates the PGO linker flag to
module A.

Test: pgo-coral-config1 in release branch, TH
Change-Id: I12f6243152d4f5ea5526fbce03c25dba232ddab7
This commit is contained in:
Pirama Arumuga Nainar 2020-09-21 22:04:25 -07:00
parent ca4536fc26
commit 1150fd7c68
1 changed files with 43 additions and 9 deletions
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52
cc/pgo.go
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@ -70,6 +70,7 @@ type PgoProperties struct {
PgoPresent bool `blueprint:"mutated"`
ShouldProfileModule bool `blueprint:"mutated"`
PgoCompile bool `blueprint:"mutated"`
PgoInstrLink bool `blueprint:"mutated"`
}
type pgo struct {
@ -89,13 +90,12 @@ func (pgo *pgo) props() []interface{} {
}
func (props *PgoProperties) addInstrumentationProfileGatherFlags(ctx ModuleContext, flags Flags) Flags {
flags.Local.CFlags = append(flags.Local.CFlags, props.Pgo.Cflags...)
flags.Local.CFlags = append(flags.Local.CFlags, profileInstrumentFlag)
// The profile runtime is added below in deps(). Add the below
// flag, which is the only other link-time action performed by
// the Clang driver during link.
flags.Local.LdFlags = append(flags.Local.LdFlags, "-u__llvm_profile_runtime")
// Add to C flags iff PGO is explicitly enabled for this module.
if props.ShouldProfileModule {
flags.Local.CFlags = append(flags.Local.CFlags, props.Pgo.Cflags...)
flags.Local.CFlags = append(flags.Local.CFlags, profileInstrumentFlag)
}
flags.Local.LdFlags = append(flags.Local.LdFlags, profileInstrumentFlag)
return flags
}
func (props *PgoProperties) addSamplingProfileGatherFlags(ctx ModuleContext, flags Flags) Flags {
@ -250,10 +250,12 @@ func (pgo *pgo) begin(ctx BaseModuleContext) {
if pgoBenchmarksMap["all"] == true || pgoBenchmarksMap["ALL"] == true {
pgo.Properties.ShouldProfileModule = true
pgo.Properties.PgoInstrLink = pgo.Properties.isInstrumentation()
} else {
for _, b := range pgo.Properties.Pgo.Benchmarks {
if pgoBenchmarksMap[b] == true {
pgo.Properties.ShouldProfileModule = true
pgo.Properties.PgoInstrLink = pgo.Properties.isInstrumentation()
break
}
}
@ -286,10 +288,42 @@ func (pgo *pgo) flags(ctx ModuleContext, flags Flags) Flags {
return flags
}
props := pgo.Properties
// Deduce PgoInstrLink property i.e. whether this module needs to be
// linked with profile-generation flags. Here, we're setting it if any
// dependency needs PGO instrumentation. It is initially set in
// begin() if PGO is directly enabled for this module.
if ctx.static() && !ctx.staticBinary() {
// For static libraries, check if any whole_static_libs are
// linked with profile generation
ctx.VisitDirectDeps(func(m android.Module) {
if depTag, ok := ctx.OtherModuleDependencyTag(m).(libraryDependencyTag); ok {
if depTag.static() && depTag.wholeStatic {
if cc, ok := m.(*Module); ok {
if cc.pgo.Properties.PgoInstrLink {
pgo.Properties.PgoInstrLink = true
}
}
}
}
})
} else {
// For executables and shared libraries, check all static dependencies.
ctx.VisitDirectDeps(func(m android.Module) {
if depTag, ok := ctx.OtherModuleDependencyTag(m).(libraryDependencyTag); ok {
if depTag.static() {
if cc, ok := m.(*Module); ok {
if cc.pgo.Properties.PgoInstrLink {
pgo.Properties.PgoInstrLink = true
}
}
}
}
})
}
props := pgo.Properties
// Add flags to profile this module based on its profile_kind
if props.ShouldProfileModule && props.isInstrumentation() {
if (props.ShouldProfileModule && props.isInstrumentation()) || props.PgoInstrLink {
// Instrumentation PGO use and gather flags cannot coexist.
return props.addInstrumentationProfileGatherFlags(ctx, flags)
} else if props.ShouldProfileModule && props.isSampling() {